Pistons And Connecting Rod Overview

Fig 1: Identifying Piston And Connecting Rod, Assembly Overview

Courtesy of AUDI OF AMERICA, LLC

1. Bolt
   • 50 Nm plus an additional 90° turn
   • Replace
   • Lubricate threads and contact surface
   • Tighten to 50 Nm to measure radial play, do not turn further
2. Connecting Rod Bearing Cap
   • Do not interchange
   • Mark affiliation to cylinder with paint, refer to Fig 7
   • Installation position of connecting rod pairs, refer to Fig 8
3. Bearing Shells
   • Check that retaining tabs are secured
   • Do not interchange used bearing shells (mark, but not on the running surface)
   • Radial clearance, measuring, refer to CONNECTING ROD, MEASURING RADIAL CLEARANCE 
   • To measure radial play, tighten bolts item -1- to 60 Nm but no further
   • Oversized bearings are available for reworked crankshaft connecting rod journals.
4. Connecting Rod
   • Only replace as set
   • Mark affiliation to cylinder with paint, refer to Fig 7
   • Installation position of connecting rod pairs, refer to Fig 8
   • Axial play for each new connecting rod pair: 0.20 to 0.27 mm
   • Axial play wear limit: 0.30 mm
   • Radial clearance, measuring, refer to CONNECTING ROD, MEASURING RADIAL CLEARANCE 
5. Piston Pin
   • If tight, heat piston to 60 °C (140 °F)
   • Removing and installing using a driftVW 222 A
6. Circlip
   • Replace
7. Piston
   • Installation position of pistons, refer to Fig 6
   • Piston and cylinder dimension, piston allocation to cylinder bore, refer to PISTON AND CYLINDER DIMENSIONS 
   • Checking, refer to Fig 4
   • Install with piston ring compressor
   • Measuring cylinder bore, refer to Fig 5
8. Piston rings
   • Offset gaps by 120°
   • Use piston ring pliers for removal and installation
   • "TOP" marking or inscribed side must point to piston head
   • Gap, measuring, refer to Fig 2
   • Measuring side clearance, refer to Fig 3

Fig 2: Checking Piston Ring Gap

Courtesy of AUDI OF AMERICA, LLC

-- Slide piston ring down from above at a right angle to cylinder wall until it is approximately 15 mm from bottom edge of cylinder.

-- When sliding in, use a piston without piston rings.

Fig 3: Checking Piston Ring Side Clearance

Courtesy of AUDI OF AMERICA, LLC

-- Clean the ring groove of piston before checking.

Fig 4: Checking Piston

Courtesy of AUDI OF AMERICA, LLC

-- Measure approximately 15 mm from the lower edge at a 90° angle to the piston pin axis using an external micrometer 75 to 100 mm.

• Maximum deviation from nominal dimension: 0.03 mm.

Nominal dimension, refer to PISTON AND CYLINDER DIMENSIONS .

Fig 5: Checking Cylinder Bores

Courtesy of AUDI OF AMERICA, LLC

-- Measure diagonally at 3 positions transversely -A- and longitudinally -B- using a inside micrometer set 18-100 mmUS1033/S or cylinder gaugeVAS 6078.

• Maximum deviation from nominal dimension: 0.08 mm.

Nominal dimension, refer to PISTON AND CYLINDER DIMENSIONS .

Fig 6: Piston Installation Position

Courtesy of AUDI OF AMERICA, LLC

Installation position:

• Arrows on piston heads point to belt pulley side.
• Large valve recesses -1- point toward center of engine.

Fig 7: Identifying Mark Connecting Rod

Courtesy of AUDI OF AMERICA, LLC

-- Mark connecting rod and connecting rod bearing cap to each other and to cylinder -arrow- with paint before removal.

Fig 8: Connecting Rod, Installed Location

Courtesy of AUDI OF AMERICA, LLC

• Molded tabs -arrows- at the beveled surfaces of the connecting rod pairs 1 and 2, 3 and 4, 5 and 6 as well as 7 and 8 must point toward each other.

Fig 9: Identifying Oil Spray Jet For Piston Cooling

Courtesy of AUDI OF AMERICA, LLC

1. Oil spray jet
2. Bolts - 9 Nm. Insert with locking compound; Locking compound.